A thief steals an ATM card and must randomly guess the correct seven-digit pin code from a 4-key keypad. Repetition of digits
1 answer:
Answer:
The probability of correct guess on the first try is .
Step-by-step explanation:
Consider the provided information.
The ATM has 4 key pad and required a 7 digit pin, where repetition is allowed.
Thief has 7 slots and 4 choices per slot. Because repetition is allowed.
Thus, the total number of different ways are:
4×4×4×4×4×4×4 = 16384
But only one combination is proper code.
Therefore,
Hence, the probability of correct guess on the first try is .
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Answer:
Step-by-step explanation:
The equation of a circle in standard form:
(h, k) - center
r - radius
We have the endpoints of the diameter: (-1, 6) and (5, -4).
Midpoint of diameter is a center of a circle.
The formula of a midpoint:
Substitute:
The center is in (2, 1).
The radius length is equal to the distance between the center of the circle and the endpoint of the diameter.
The formula of a distance between two points:
Substitute the coordinates of the points (2, 1) and (5, -4):
Finally we have: